BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to an electron-emitting device, and more particularly
to a surface conduction electron-emitting device that emits electrons when an electric
current is flowed in a highly resistant thin film.
Related Background Art
[0002] Hitherto known as a device capable of emitting of electrons with a simple structure
is the cold cathode device reported by M.I. Elinson et al (Radio Eng. Electron. Phys.,
Vol. 10, pp.1290-1296, 1965).
[0003] This utilizes the phenomenon that electron emission is caused by flowing an electric
current to a thin film formed with a small area on a substrate and in parallel to
the surface of the film, and is generally called a surface conduction electron-emitting
device.
[0004] This surface conduction electron-emitting device that has been reported includes
those employing a SnO₂ (Sb) thin film developed by Elinson et al., those employing
an Au thin film. (G. Dittmer, "Thin Solid Films", Vol. 9, p.317, 1972), those comprising
an ITO thin film, (M. Hartwell and C.G. Fonstad, "IEEE Trans. ED Conf.", p.519, 1975),
and those comprising a carbon thin film [Hisaji Araki, "SHINKU" (Vacuum), Vol. 26,
No. 1, p.22, 1983)
[0005] Typical device constitution of these surface conduction electron-emitting devices
is shown in Fig. 17. In Fig. 17, a conventional surface conduction electron-emitting
device comprises an insulating substrate 5 having thereon a highly resistant thin
film 4 provided between a high-potential electrode 1 and a low-potential electrode
2, where a voltage is applied from an external electric source 3 and thereby electrons
are emitted from the highly resistant thin film 4.
[0006] In these surface conduction electron-emitting devices, it has been hitherto practiced
to previously form an electron-emitting region 4 (a high-resistance thin film) by
an energizing heat treatment, called "forming", before effecting the electron emission.
More specifically, a voltage is applied between the above electrode 1 and electrode
2 to energize the thin film formed with an electron-emitting material to bring the
thin film to be locally destroyed, deformed or denatured owing to the Joule heat thereby
generated, thus forming the electron-emitting region 4 (a high-resistance thin film)
kept in a state of electrically high resistance to obtain an electron-emitting function.
[0007] However, such a conventional surface conduction electron-emitting device has disadvantages
such as the following:
(1) The light-emitting region flickers.
(2) As shown in Fig. 18, the electron beam tends to deflect by the distance L toward
ther high-potential electrode 1 side, and in general the beam diverges.
(3) Accordingly, as shown in Fig. 19 it is necessary to externally provide a focusing
lens system to effect the focusing of the electron beam. This, however, requires preparation
of external focusing lenses 17 and 18, requiring an additional step correspondingly.
(4) There is required a complicated operation to make axial alignment on the basis
of electron optics between the outer focusing lenses 17 and 18 and the surface conduction
electron-emitting device.
SUMMARY OF THE INVENTION
[0008] An object of the present invention is to provide a surface conduction electron-emitting
device that can solve the problems as mentioned above, caused by the insufficiency
in the focusing performance, and can achieve a good beam-focusing performance without
requiring any external focusing lenses 17 and 18.
[0009] The above object can be achieved by the invention as described in the following.
[0010] According to an aspect of the present invention, there is provided surface conduction
electron-emitting device comprising a high-potential electrode provided on a substrate
surface, an electron-emitting region provided in contact with the periphery of an
exposed part of said high-potential electrode, and a low-potential electrode further
provided in contact with the periphery of said electron-emitting region.
[0011] According to another aspect of the present invention, there is provided a surface
conduction electron-emitting device comprising a high-potential electrode provided
on a substrate surface, an electron-emitting region provided in contact with the
periphery of an exposed part of said high-potential electrode, and a low-potential
electrode further provided in contact with the periphery of said electron-emitting
region in such a manner that it projects upward in the thickness direction of the
substrate to a higher level than the high-potential electrode.
[0012] According to a further aspect of the present invention, there is provided a surface
conduction electron-emitting device comprising a high-potential electrode provided
on a substrate surface, an electron-emitting region provided in contact with the
periphery of an exposed part of said high-potential electrode, a low-potential electrode
further provided in contact with the periphery of said electron-emitting region, and
a means for applying a voltage between said high-potential electrode and low-potential
electrode.
[0013] According to a still further aspect of the present invention, there is provided a
surface conduction electron-emitting device comprising a high-potential electrode
provided on a substrate surface, an electron-emitting region provided in contact with
the periphery of an exposed part of said high-potential electrode, a plurality of
low-potential electrods provided in contact with the periphery of the electron-emitting
region, and means for applying different potential independently to each of said low-potential
electrodes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014]
Fig. 1, Fig. 3 to Fig. 8B and 10A to Fig. 14 are views illustrating surface conduction
electron-emitting devices of the present invention;
Fig. 2 is a view explanatory of how electrons emit from the surface conduction electron-emitting
device of the present invention;
Figs. 9A and 9B are views explanatory of how equipotential lines are formed on the
surface conduction electron-emitting devices of the present invention;
Fig. 15A to Fig. 16G are flow sheets each showing the manner by which the surface
conduction electron-emitting device of the present invention is prepared;
Fig. 17 and Fig. 19 are views illustrating a conventional surface conduction electron-emitting
device; and
Fig. 18 is a view explanatory of how electrons emit from the conventional surface
conduction electron-emitting device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] The present invention will be specifically described below with reference to the
accompanying drawings.
[0016] Fig. 1 is a basic block diagram illustrating an example of the surface conduction
electron-emitting device of the present invention. In Fig. 1, the surface conduction
electron-emitting device of the present invention comprises a pair of electrodes,
of which a high-potential electrode 1 having a round shape and feeding an electric
current to an electron- emitting region 4 is concentrically provided on its periphery
with the electron-emitting region 4, and a low-potential electrode is similarly concentrically
provided around the electron-emitting region 4.
[0017] In such constitution, the potential is constant everywhere on the respective electrodes.
In the conventional surface conduction electron-emitting device illustrated in Fig.
17, the high-potential electrode 1 and the low-potential electrode 2 are separated
right and left to form line symmetry, while in the device of the present invention
illustrated in Fig. 1, the electrode form center symmetry and rotation symmetry to
being about remarkably high symmetricalness as a whole. For this reason, the velocity
distribution of the electrons to be emitted may be neither irregular not deflected
in contrast with the prior art, but can be uniform distribution having the center
symmetricalness and rotation symmetricalness, so that the electron beam emitted from
the surface conduction electron-emitting device can be focused at a particular position,
i.e., a spot located at the direction perpendicular to the center of said device,
and moreover decrease the flickering due to the substantial increase of the area of
the light-emitting region.
[0018] Fig. 2 is a view explanatory of how electrons emit from the surface conduction electron-emitting
device of the present invention. In Fig. 2, when a voltage is applied to an accelerating
electric source 6, electrons tend to converge to the center as a whole as indicated
by arrow A. This is because the potential distribution is generated such that the
electrons are inclined to focus to the high-potential side at the center since the
high-potential electrode 1 has a high potential and the low-potential electrode has
a low potential. For this reason, a good focusing performance can be achieved when
electrons are focused to a target electrode 9 with use of the accelerating electric
source 6, even without providing any external focusing lenses such as lens electrodes
17 and 18 as illustrated in Fig. 19 of the prior art. Accordingly, such a surface
conduction electron-emitting device of the present invention, as having the structure
that the electrodes 1 and 2 and focusing lenses 17 and 18 of the prior art have been
integrated to the high-potential electrode 1 and low-potential electrode, makes it
possible to bring the electrons to focus to a specific part, i.e. a vertically upper
part of the center of said device.
[0019] In addition, in the surface conduction electron-emitting device of the present invention,
the electrodes and the electron-emitting region may not necessarily have the round
shapes. For example, the same effect as previously stated can be obtained even when
as illustrated in Fig. 3, Fig. 4 and Fig. 5, the low-potential electrode is divided
into a plural number of electrodes to provide a plural number of electron-emitting
regions of curved or linear shapes, so long as the device basically comprises a high-potential
electrode provided on a substrate surface, an electron-emitting region provided in
contact with the periphery of an exposed part of said high-potential electrode, and
a low-potential electrode further provided in contact with the periphery of said electron-emitting
region. Here, in the instance where the electron-emitting region is made to have the
curved shape, the high-potential electrode may preferably have a round or oval shape
(as exemplified by the devices having the electron-emitting region as illustrated
in Fig. 1, 3 and 4). Also, in the instance where the electron-emitting region 4 is
made to have the linear shape, the high-potential electrode 1 may preferably have
a polygonal shape (as exemplified by those illustrated in Fig. 5).
[0020] In the surface conduction electron-emitting device illustrated in Fig. 4, comprising
the high-potential electrode having a round shape and the low-potential electrode
made to be composed of four electrodes 2a to 2d, the device is so constituted that
the low-potential electrodes 2b and 2d can be selected whether they work as low-potential
electrodes (ON) or not (OFF), by means of a switch 10a, and, similarly, ON/OFF of
the low-potential electrodes 2a and 2c can be selected by means of a switch 10b. Here,
electron-emitting regions 4b and 4d provided between the high-potential electrode
1 and the low-potential electrodes 2b and 2d constitutes one set of electron-emitting
regions (referred to as Set I), and, similarly, 4a and 4c constitute one set (referred
to as Set II).
[0021] The ON/Off of the electron-emitting regions of Set I and that of the electron-emitting
regions of Set II can be selected by the switch 10a and switch 10b, respectively.
Accordingly, the switch 10b may be kept turn off and only switch 10a may be turned
on to drive the surface conduction electron-emitting device of the present invention,
so that there is given an electron-emitting device in which the center of the light-emitting
region is positioned vertically above the center of the surface conduction electron-emitting
device of the present invention and a space electron-emitting region is provided
corresponding to Set II that makes provisions for the case when the electron-emitting
regions of Set I turned impossible for use because of end of life of the electron-emitting
regions.
[0022] As illustrated in Fig. 6C, the surface conduction electron-emitting device of the
present invention may also be a 'vertical type' surface conduction electron-emitting
device comprising;
a pair of electrodes 1 and 2b positioned on and beneath a stepped portion of a step-forming
layer 15 provided on a substrate 12, said electrodes 1 and 2b oposing each other with
said stepped portion between to have electrode spacing; and
an electron-emitting region 4b formed at the side end face of the stepped portion
positioned between said electrodes 1 and 2b;
where electrons are emitted from the electron-emitting region 4b on applying a voltage
between the electrodes 1 and 2b. In this embodiment also, the beam of emitted electrons
can be brought to focus, so long as the device has the form, as illustrated in Fig.
6A, 6B and 6C, comprising a high-potential electrode 1 provided on a substrate surface,
electron-emitting regions 4 and 4a to 4d provided in contact with the periphery of
an exposed part of said high-potential electrode, and low-potential electrodes 2
and 2a to 2d further provided in contact with the peripheries of said electron-emitting
regions 4 and 4a to 4d.
[0023] In a surface conduction electron-emitting device of the type that the low-potential
electrode described above is divided in plurality so as to provide a plural number
of electron-emitting regions in one device, the electron beam can also be brought
to deflect to a desired direction by independently applying different potential to
each of the low-potential electrodes.
[0024] As an example thereof, as illustrated in Fig. 7, a low-potential electrode 2 is divided
into two parts, 2a and 2b, to which potential Va, Vb is independently applied. Namely,
if Va > Vb, the beam deflects toward 2a, and, in the reverse, it deflects toward 2b.
In this occasion, the direction and magnitude of the deflection depends on Va minus
Vb, and the amount of emitted electrons and the degree of focusing substantially depend
on Va plus Vb. Accordingly, the both can be controlled independently. Additionally
speaking, the low-potential electrode 2 need not be divided into two parts, and can
be divided into desired number of electrodes according to what purpose the device
is used for.
[0025] Next, in the surface conduction electron-emitting device of the present invention,
the focusing performance of the electron beam can be more improved by providing a
low-potential electrode in such a manner that it projects upward in the thickness
direction of the substrate to a higher level than the high-potential electrode.
[0026] For example, as shown in Figs. 8A and 8B, when the device takes the constitution
that a high-potential electrode 1 has a round shape and is surrounded by a low-potential
electrode forming a hole in between, the diameter d₁ of the high-potential electrode
1, the diameter d₂ of the hole defined by the low-potential electrode 2 and the height
h of the hole (or the distance from the top surface of the high-potential electrode
to the top surface of the low-potential electrode) may preferably satisfy the following
relationship:
d₂ - d₁ ≲ 4 µm (a)
d₂/6 ≲ h ≲ 6 d₂ (b)
[0027] How the electron beam focusing performance is improved by virtue of the electrodes
1 and 2 will be described here with reference to Figs. 9A and 9B.
[0028] In Figs. 9A and 9B, the numeral 1 denotes a high-potential electrode; 2, a low-potential
electrode; and 4, an electron-emitting region. Though not illustrated here, assume
that a plane target electrode to which a positive voltage of several to several ten
kV has been applied is disposed above the surface conduction electron-emitting device.
[0029] Fig. 9A shows equipotential lines in the vicinity of a surface conduction electron
emitting device comprising electrodes 1 and 2 both made equal in thickness, and the
direction of a representative force exerted to the electron beam, which is indicated
by arrows F. Similarly, Fig. 9B shows a state in the vicinity of a surface conduction
electron-emitting device comprising the low-potential electrode 2 projected upward
in the thickness direction of the substrate to a higher level than the high-potential
electrode 1. As will be seen by comparing these Fig. 9A and Fig. 9B, in the surface
conduction electron-emitting device of the present invention, the slant of equipotential
lines is greater in the case where the low-potential electrode 2 has a larger thickness
than the high-potential electrode 1, as compared with that in Fig. 9A. Accordingly,
the electron beam undergoes a greater focusing force toward the center at the emission
initial stage in which it has a small magnitude of the velocity component toward the
target electrode and is subject to influence by the electric field.
[0030] In Figs. 8A and 8B, the electrodes and electron-emitting regions have round shapes,
but the same effect as previously stated can be obtained even when as illustrated
in Fig. 10, Fig. 11 and Fig. 12, the low-potential electrode is divided into a plural
number of electrodes to provide a plural number of electron-emitting regions of curved
or linear shapes, so long as the device comprises a high-potential electrode provided
on a substrate surface, an electron-emitting region provided in contact with the
periphery of an exposed part of said high-potential electrode, and a low-potential
electrode further provided in contact with the periphery of said electron-emitting
region in such a manner that it projects upward in the thickness direction of the
substrate to a higher level than the high-potential electrode.
[0031] In the surface conduction electron-emitting device of the present invention, unevenness
as illustrated in Figs. 13A to 13C may further be made on at least one of the boundary
between the low-potential electrode and the electron-emitting region and the boundary
between the high-potential electrode and the electron-emitting region. Forming the
boundary in such a shape makes stronger the local electric field desirably. Also,
as illustrated in Fig. 13D, the low-potential electrode 2 can be made to have any
desired outer side shape according to any conditions of arrangement or wiring.
[0032] As illustrated in Fig. 14, the surface conduction electron-emitting device according
to the present invention may also constitute a plural number of devices arranged on
the same substrate and driven independently, so that there can be obtained a plural
number of independent electron beams.
[0033] An example of methods for preparing the surface conduction electron-emitting device
of the present invention will be described below with reference to Figs. 15 and Figs.
16. In Figs. 15A to 15E, the surface of a substrate 16 is first oxidized to form an
insulating film, thus preparing an insulating substrate 5 (Fig. 15A). Next, part of
the insulating substrate 5 is etched to make a hole, and thereafter a metal film 20
is formed on the whole surface by vapor deposition (Fig. 15B). This metal film 20
is further etched as illustrated in Fig. 15C to prepare a high-potential electrode
1 and low-potential electrodes 2a and 2c. Next, a thin film 21 is formed by vapor
deposition, and then a forming treatment is carried out (Fig. 15D). In this instance,
unless the high-potential electrode 1 and the low-potential electrodes 2a and 2c are
masked, the thin film adheres also on top surfaces of these, but this does not affect
the characteristics of the device in practical use. If necessary, however, it is of
course possible to cover with a mask the top surfaces of the high-potential electrode
1 and low-potential electrodes 2a and 2c to prevent the thin film from adhering thereon.
Then, application of a voltage between the low-potential electrodes 2a and 2c and
the substrate 16 from an external electric source 3 brings about emission of electrons
from electron-emitting regions 4a and 4c (Fig. 15E).
[0034] To describe another method for preparing the surface conduction electron-emitting
device of the present invention, with reference to Figs. 16A to 16G, a wiring electrode
14 is first patterned in the shape of a stripe on a substrate 12 made of glass, quartz
or the like (Fig. 16A). Next, an insulating layer 13 is formed on the substrate 12
and wiring electrode 14 (Fig. 16B), and this insulating layer 13 is worked to make
a hole by etching as illustrated in Fig. 16C. Subsequently, a metal film is formed
by vapor deposition, followed by etching to prepare a high-potential electrode 1
(Fig. 16 D). A thin film 4 is further formed by vapor deposition and a forming treatment
is carried out (Fig. 16E). Then a metal film 2 that formed the high-potential electrode
1 is formed by vapor deposition (Fig. 16F), followed by working to make a hole by
etching to prepare low-potential electrode 2a and 2c (Fig. 16G).
[0035] In the above methods, electron-emitting regions 4a and 4c (figs. 15 and 16) are formed
by vapor deposition, but, without limitation thereto, also available is a method in
which a dispersion obtained by dispersing fine particles of an electron-emitting
material in a dispersion medium is applied by, for example, dipping or spin coating,
followed by baking. In this instance, the dispersion medium may be any of those capable
of dispersing the fine particles without any change of their properties, and there
may be used, for example, alcohols, methyl ethyl ketone, cyclohexane, and a mixture
of any of these. The fine particles may preferably have a particle diameter of several
ten angstroms to several um.
[0036] Materials will be described below.
[0037] Materials for constituting the surface conduction electron-emitting device of the
present invention may be any of those used in conventional surface conduction electron-emitting
devices. For example, the substrate 16 (Fig. 15) may be made of any materials so long
as they are electroconductive, including n-type Si, P-Si, or metals such as Al and
Cu. The high-potential electrode 1 and low-potential electrodes 2a and 2c (Figs. 15
and 16), and also the wiring electrode 14 (Fig. 16) may also be made of any materials
so long as they are good conductors, and there can be used, for example, metals such
as Cu, Pb, Ni, Al, Au, Pt and Ag, and oxides such as SnO₂ and ITO.
[0038] The insulating substrate 5 (Fig. 15) may also be made of any materials so long as
the insulating film formed thereon comprises an insulator, but what can be simple
in view of preparation methods may preferably include SiO₂ and Al₂O₃ obtainable by
oxidation of the substrate. Insulators such As SiO₂, MgO and glass are also used in
the substrate 12 and insulating layer 13 (Fig. 16).
[0039] Further used in the electron-emitting regions 4a, 4c (Figs. 15 and 16) are, for example,
metal oxides such as as In₂O₃, SnO₂ and PbO, metals such as Ag, Pt, Al, Cu and Au,
carbon, and other various semiconductors.
[0040] As for the size of each component, the high-potential electrode 1 may be made to
have a size of from 1 nm to several mm, the electron-emitting regions 4a and 4c may
each have a width of the size corresponding to that of a conventional surface conduction
electron-emitting device (for example, 1 µm to several ten mm), and the low-potential
electrodes 2a and 2c may have any size.
[0041] The electron-emitting regions 4a and 4c may also each have a thickness corresponding
to that of a conventional surface conduction electron-emitting device (for example,
several ten Å to several µm). The high-potential electrode 1 and the low-potential
electrodes 2a and 2c may have any thickness. Since, however, an excessively large
thickness may cause hindrance of electron emission, the high-potential electrode 1
may desirably have a little larger thickness than the film thickness of the electron-emitting
regions. The insulating substrate may have any thickness.
[0042] When the low-potential electrodes 2a and 2c are formed to have a larger thickness
than the high-potential electrode 1, in order to they improve the electron beam focusing,
should be formed so as to satisfy the relationship of the formulas (a) and (b) previously
described.
[0043] In case where a number of the surface conduction electron-emitting devices are provided
in arrangement, the wiring electrode 14 may be formed on the substrate 12 by patterning
to have a desired shape such as a stripe on a desired position and then the high-potential
electrode 1 may be provided on this wiring electrode 14 as shown in Figs. 16, thus
preferably making easy the manufacture.
[0044] In the instance where the surface conduction electron-emitting device of the present
invention has a vertical type structure previously described, an insulating material
is used in general as the step-forming layer 15 as illustrated in Fig. 6C and Fig.
12C. For example, the material may be SiO₂, MgO, TiO₂, Ta₂O₅ and Al₂O₃, a laminate
of any of these, or a mixture of any of these. The spacing between the electrodes
1 and 2 depends on the thickness of the step-forming layer 15 and the thickness of
the electrodes 1 and 2, but may preferably be several ten angstroms to several um.
Other component members may employ the same materials and constitution as those previously
described.
[0045] As described above, the surface conduction electron-emitting device of the present
invention comprises a high-potential electrode provided on a substrate surface, an
electron-emitting region provided in contact with the periphery of an exposed part
of said high-potential electrode, and a low-potential electrode further provided
in contact with the periphery of said electron-emitting region. It is possible to
focus the electron beam to a particular position, i.e., a spot located at the direction
perpendicular to the center of said device, and moreover decrease the flickering at
the light-emitting region. Also, if the low-potential electrode of said device is
divided into a plural number of electrodes to provide a plural number of electron-emitting
regions, it is possible for the surface conduction electron-emitting device of the
present invention to be provided with a spare electron-emitting region. In addition,
the surface conduction electron-emitting device of the present invention, when taking
the constitution comprising an inside high-potential electrode and an outside low-potential
electrode projecting upward in the thickness direction of a substrate, can further
enhance the beam-focusing performance, make smaller the size of the electron beam
on a target electrode, and make it unnecessary to provide any external focusing lenses.
Example 1
[0046] A surface conduction electron-emitting device was prepared in a manner shown in figs.
15A to 15E.
[0047] The surface of an n-type Si substrate was oxidized to form an insulating film comprising
SiO₂, and part thereof was etched to make a hole, followed by vapor deposition of
an Al metal film on the whole surface. The resulting deposited film was further etched
to prepared high-potential and low-potential electrodes. A thin Au film was further
formed thereon by vapor deposition, and a forming treatment was carried out, thus
obtaining the surface conduction electron-emitting devices illustrated each in Fig.
1 and Fig. 5.
[0048] Employment of this surface conduction electron-emitting device brought about a decrease
in the flickering as in the prior art. Here, assuming the electron electric current
ejected from the surface conduction electron-emitting device and I
e, the swing of the electron electric current as ΔI
e, and ΔI
e/I
e as an index of the flickering at the light-emitting region, the surface conduction
electron-emitting device of the present invention showed about 1/2 flicker as compared
with 16 % flicker in the conventional device (Fig. 17), and the center of the light-emitting
spot was positioned at the direction perpendicular to the center of the surface conduction
electron-emitting device.
Example 2
[0049] Example 1 was repeated to prepare the surface conduction electron-emitting device
illustrated in Fig. 3. The flickering at the light-emitting region thereof was 1/1.4
of that in the prior art. The center of the light-emitting spot was also positioned
at the direction perpendicular to the center of the device.
Example 3
[0050] Example 1 was repeated to prepare the surface conduction electron-emitting device
illustrated in Fig. 4. The flickering at the light-emitting region thereof was 1/1.4
of that in the prior art. The center of the light-emitting spot was also positioned
at the direction perpendicular to the center of the device.
Example 4
[0051] A surface conduction electron-emitting device was prepared in a manner shown in Figs.
16A to 16G.
[0052] In Figs. 8A and 8B, the numeral 12 denotes a glass substrate, and 14 denotes a wiring
electrode which is provided in a stripe pattern on the substrate 12. The material
for the wiring electrode 14 was comprised of a laminate of Cr of 50 angstroms thick
and Ta of 1,000 angstroms thick.
[0053] The numeral 13 denotes an insulating layer, which was formed by coating a liquid
SiO₂ coating preparation (OCD, available from Tokyo Ohka Kogyo) to a thickness of
1 micron.
[0054] Photolithoetching was conducted to make a hole in the insulating layer 13, followed
by deposition of Cu to a thickness of 1.2 µm thereon, and the copper other than that
necessary for the high-potential electrode 1 was removed by photolithoetching.
[0055] Subsequently, as an electron-emitting material, a solution of an organic palladium
compound (Catapaste CCP, available from Okuno Seiyaku Kogyo) was applied thereon by
spinner coating. Thereafter, the coating was baked for 1 hour at 400°C to prepare
a thin film 4 having a film thickness of 1,500 angstroms and containing Pd fine particles.
[0056] Next, as a low-potential electrode 2, Al was vapor deposited to a thickness of 10
µm, and, as shown in Fig. 8A and Fig. 8B, the peripheral area of the high potential
electrode 1 was removed by conventional photolithoetching. At the same time, the low-potential
electrode 2 was etched to give the shape of a stripe serving also as a wiring electrode.
[0057] The diameter d₁ of the high-potential electrode 1, the diameter d₂ of the hole of
the low-potential electrode 2, and the height h thereof were made to have the following
relationship:
d₁ ∼ 10 µm
d₂ ∼ 14 µm
h ∼ 10 µm
[0058] Application of a voltage of 10 to 20 V applied between the electrode 1 and the electrode
2 brought about emission of electrons from the electron-emitting region 4a.
[0059] At an upper part of the surface conduction electron-emitting device as in the above,
placed was a target electrode coated with a phosphor and applied with an accelerated
voltage, and the spreading of the electron beam was measured. As a result, it was
confirmed that the spreading was about 3/5 with a remarkable enhancement of the focusing
performance, as compared with a surface conduction electron emitting device comprising
electrodes 1 and 2 both made equal in thickness.
Example 5
[0060] The present Example will be described making reference to Fig. 10.
[0061] In the present Example, the device was made to have the same structure as in Example
4 except that the high-potential electrode 1 was held between two thick low-potential
electrodes 2a and 2b from the both sides.
[0062] A remarkable enhancement of the focusing performance was confirmed also in the present
Example.
Example 6
[0063] The present Example will be described making reference to Fig. 11.
[0064] In the present Example, the device was made to have the same structure as in Example
4 except that the high-potential electrode 1 was surrounded by four thick low-potential
electrodes 2a to 2d.
[0065] A remarkable enhancement of the focusing performance was confirmed also in the present
Example.
1. A surface conduction electron-emitting device comprising as high-potential electrode
provided on a substrate surface, an electron-emitting region provided in contact with
the periphery of an exposed part of said high-potential electrode, and a low-potential
electrode further provided in contact with the periphery of said electron-emitting
region.
2. The surface conduction electro-emitting device of Claim 1, wherein said low-potential
electrode is divided into a plural number of electrodes.
3. The surface conduction electron-emitting device of Claim 1, wherein uneveness is
made on the side coming into contact with the electron-emitting region, of at least
one electrode of the high-potential electrode and the low-potential electrode.
4. The surface conduction electron-emitting device of Claim 1, comprising a means
for applying a voltage between the high-potential electrode and the low-potential
electrode, and flowing an electric current to the electron-emitting region to bring
electrons to emit from the electron-emitting region.
5. A surface conduction electron-emitting device comprising a high-potential electrode
provided on a substrate surface, an electron-emitting region provided in contact with
the periphery of an exposed part of said high-potential electrode, and a low-potential
electrode further provided in contact with the periphery of said electron-emitting
region in such a manner that if projects upward in the thickness direction of the
substrate to a higher level than the high-potential electrode.
6. The surface conduction electron-emitting device of Claim 5, wherein said low-potential
electrode is divided into a plural number of electrodes.
7. The surface conduction electron-emitting device of Claim 5, wherein unevenness
is made on the side coming into contact with the electron-emitting region, of at least
one electrode of the high-potential electrode and the low-potential electrode.
8. The surface conduction electron-emitting device of Claim 5, comprising a means
for applying a voltage between the high-potential electrode and the low-potential
electrode, and flowing an electriccurrent to the electron-emitting region to bring
electrons to emit from the electron-emitting region.
9. A surface conduction electron-emitting device comprising a high-potential electrode
provided on a substrate surface, a electron-emitting region provided in contact with
the periphery of an exposed part of said high-potential electrode, a low-potential
electrode further provided in contact with the periphery of said electron-emitting
region, and a means for applying a voltage between said high-potential electrode
and low-potential electrode.
10. The surface conduction electron-emitting device of Claim 9, wherein said electron-emitting
region emits electrons on flowing an electric current.
11. The surface conduction electron-emitting device of Claim 9, wherein said low-potential
electrode is divided into a plural number of electrodes.
12. The surface conduction electron-emitting device of Claim 9, wherein said means
for applying a voltage is means for applying an equal magnitude of potential, to a
plurality of low-potential electrodes.
13. The surface conduction electron-emitting device of Claim 9, wherein unevenness
is made on the side coming into contact with the electron-emitting region, of at least
one electrode of the high-potential electrode and the low-potential electrode.
14. The surface conduction electron-emitting device of Claim 9, wherein said low-potential
electrode projects upward in the thickness direction of the substrate to a higher
level than the high-potential electrode.
15. A surface conduction electron-emitting device comprising a high-potential electrode
provided on a substrate surface, an electron-emitting region provided in contact with
the periphery of an exposed part of said high-potential electrode, a plurality of
low-potential electrodes provided in contact with the periphery of said electron-emitting
region, and a means for applying different potential independently to each of said
low-potential electrodes.
16. The surface conduction electron-emitting device of Claim 15, wherein said electron-emitting
region emits electrons on flowing an electric current.
17. The surface conduction electron-emitting device of Claim 15, wherein said means
for applying different potential is a means capable of independently adjusting the
magnitude of the potential to be applied to each low-potential electrode.
18. The surface conduction electron emitting device of Claim 15, wherein said low-potential
electrode projects upward in the thickness direction of the substrate to a higher
level than the high-potential electrode.
19. The surface conduction electron-emitting device of Claim 15, wherein unevenness
is made on the side coming into contact with the electron-emitting region, of at least
one electrode of the high-potential electrode and the low-potential electrode.